Move cgroups package into libcontainer

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)

libcontainer/cgroups/fs/utils_test.go

@@ -0,0 +1,68 @@
+package fs
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+const (
+	cgroupFile  = "cgroup.file"
+	floatValue  = 2048.0
+	floatString = "2048"
+)
+
+func TestGetCgroupParamsFloat64(t *testing.T) {
+	// Setup tempdir.
+	tempDir, err := ioutil.TempDir("", "cgroup_utils_test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tempDir)
+	tempFile := filepath.Join(tempDir, cgroupFile)
+
+	// Success.
+	err = ioutil.WriteFile(tempFile, []byte(floatString), 0755)
+	if err != nil {
+		t.Fatal(err)
+	}
+	value, err := getCgroupParamFloat64(tempDir, cgroupFile)
+	if err != nil {
+		t.Fatal(err)
+	} else if value != floatValue {
+		t.Fatalf("Expected %f to equal %f", value, floatValue)
+	}
+
+	// Success with new line.
+	err = ioutil.WriteFile(tempFile, []byte(floatString+"\n"), 0755)
+	if err != nil {
+		t.Fatal(err)
+	}
+	value, err = getCgroupParamFloat64(tempDir, cgroupFile)
+	if err != nil {
+		t.Fatal(err)
+	} else if value != floatValue {
+		t.Fatalf("Expected %f to equal %f", value, floatValue)
+	}
+
+	// Not a float.
+	err = ioutil.WriteFile(tempFile, []byte("not-a-float"), 0755)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = getCgroupParamFloat64(tempDir, cgroupFile)
+	if err == nil {
+		t.Fatal("Expecting error, got none")
+	}
+
+	// Unknown file.
+	err = os.Remove(tempFile)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = getCgroupParamFloat64(tempDir, cgroupFile)
+	if err == nil {
+		t.Fatal("Expecting error, got none")
+	}
+}